During the manufacturing of textiles and during washing textiles, as a result, a certain brittling of the materials sets in in most textiles. To eliminate this inconvenience, treating methods are employed to restore softness and suppleness to the textiles or to redefine the character of the material according to fashion viewpoints. In addition, technical requirements such as antistatics, wrinkle recovery, yellowing, surface smoothness, and the like, are considered in determining further treatment of the textiles.
It is known that quaternary tetraalkyl-ammonium compounds with two long-chained, generally C.sub.16 -C.sub.18 alkyl radicals are suitable as softening agents. These textile softeners are used widely, on the one hand, in the manufacture of textiles and, on the other hand, in the treatment of textiles both in commercial laundries and in households. It is assumed that these cationic quaternary ammonium compounds are easily absorbed on the textile substrate because of their positive charge.
The most frequently used textile softener of this compound class is ditallow-alkyl- or distearyldimethyl ammonium chloride. This textile softener has excellent softening properties, as well as tinctorial power and substantivity, and can be used under all normal conditions both in the finishing and in the care of textiles. However, it also has drawbacks. For example, the commonly used cationic softeners yellow at the drying and/or condensation or thermofixing temperatures used in the textile industry, a property which is not acceptable in white goods or pastel-colored articles. Another drawback of the cationic softeners is that the textiles finished with them become hydrophobic, which is particularly undesirable with regard to cellulose fibers, which are especially used for their excellent absorption power in sanitary articles, such as cotton, diapers, sanitary napkins, or tampons, or in terry- and tricot materials.
In treating synthetic fibers, the antistatic effect of such textile softeners becomes apparent, in addition to the softening property or the softening treatment. However, the softening treatments representing the state of the art have only a modest effect. The textiles treated with these substances show reduced absorbency, as compared to untreated fabrics, which results in unpleasant feel to the user in, for example, garments worn in contact with the skin and Turkish towels. Frequently these textile softeners can not be completely removed from the fabric by washing, so that even when the softening substances are used in proper dosage, they sometimes accumulate. This likewise results in a reduced absorbency of the textiles.
Another serious drawback of these textile softeners is their relatively high production cost, since it is necessary to start from secondary fatty amines which are obtained primarily from natural fatty acids or fatty alcohols of frequently varying quality.
There has been no lack of attempts to eliminate these drawbacks. Thus, it is known from U.S. Pat. No. 3,636,114 that absorbency can be improved by using quaternary ammonium compounds with two long-chained 2-hydroxyalkyl radicals. German Published Application (DOS) No. 22 56 234 discloses quaternary ammonium compounds with two long-chained 2-hydroxy-3-alkoxypropyl groups. The softeners known from German Published Application (DAS) No. 16 19 043 contain quaternary ammonium compounds with only one long alkyl radical and three short alkyl radicals, where the three short alkyl radicals can contain hydroxyl or ether groups. Dutch Patent Application N. 68/08958 and U.S. Pat. No. 3,591,405 describe ammonium compounds whose hydrophobic radicals represent hydroxyalkyl-groups or alkyl groups linked with the nitrogen by ethoxy groups. However, these solutions were not satisfactory, either because the modified quaternary ammonium compounds were difficult to produce, and thus unsuitable for use in practice, or because the softening action was too weak.
Applicants have surprisingly found that useful quaternary compounds can be prepared in a relatively straightforward manner from readily available, inexpensive raw materials. These compounds, which impart absorbency and good softening properties during the processing or washing of treated textiles, can be removed completely when the textiles are washed.